Automatic telephone system



March 27, 192s.

R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM lO Sheets-Sheet 1 Orginal- Filed June 25, 1923 Mutu@ mutue.

March 27, 1928.

R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Original Filed June 25, 1923 l0 Sheets-Sheet 2 MUT@ March 27, 192s. y

' R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Original Filed June 25, 1923 lO Sheets-Sheet 3 March 27, 1928. 1,663,860

R. G. RICHARDSON AUTOMATI C TELEPHONE S YSTEM Original Filed June 25, 1923 lO Sheets-Sheet 4 1 T Q @T Imran L713- .End-neg l?. .Efzchard'san March 27, 1928.

R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM lO Sheets-Sheet 5 Original Filed June 25, 1923 E Hlcharursan March 27, 192s.

R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Original Filed June 25, 1923 10 Sheets-Sheet 6 *IWW- Urns E. Bwhard'snn NSN March 27, 192:5.v j 1,663,660

R. G. RICHARDSON 4AUTOMATIC TELEPHONE SYSTEM fad 0 Sheets-She@ 7 Original Filed Im-'- HDC/hay EBmhard'snn HIT.'

March 27, 1928. 1,663,860

` R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Original Filed Jme 25, 1925 l0 Sheets-Sheet 8 l, l Y 44?/ T Fzg: E

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Bnurner E. Elisharsnn March 27, 1928.

l R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM originai Filed Jne 25, 1923 10- Sheets-Sheet 9 v mix www OR. www

0 m 6 m q. 6, wkn 1.. wm MNHN S\\m\ o 1 M 3 N mm Y s w, D m R m M M w C m d m T n .1 C F 1 SQ w\\ MM NN G. u DR R w T U A om 2 9 1 7, 2 .m Mu Em@ v Inman C113- HUC/'nay E Ezahard'snn Patented Mar. 27, 1928.

uNVriznfsmir-Es"v RODNEY G. `RICHARDSON, OF CHICAGO,`ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION 0F DELA- WARE.

Application mea June 25, 1923, serial The present'invention relates in general't-o automatic telephone systems, but more particularly to such systems as vemploy-the so called director for controlling the establishment ofconnections, andthe general object is to provide an improved type of director which is adapted to translate from one system of notation to another. JMore specifically, the object is to provide a director, or translator and sender, for` use in a multi-office automatic telephone system in which the numbers are received according ardson et al., S. N. 638,551, filed March 29,

1.922; Ray, S. N. 589,985, filed Sept. 23, 1922; Gillings, S. N. 598,239, filed Nov. 1,1922.

There are various other lobjects having to do mainly with the detailed workings of the system that can be gathered best from the detailed description of the Yoperation of the system. v

In illustrating the invention, it will be assumed that the numbers received by the directorsare writtenA according to the system of notation in which twenty characters are used,`and are then translated into numbers'written according to thefdecimal system of notation.V The twenty character system of notation permits each ofa large number of subscribers to be listed by means of va number vcontaining a small number ofl characters as compared with the number of characters required when the decimal system of notation is used to list-a like' number vvof subscribers. The'advantages of using a sysi tem ofnotation in which a reduction of the number of characters in the number is permitted have been set forth in numerous patents, and the greatest one is probablythe advantage gained on account of the fact that the numbers, being shorter, are muchmore easily carried.r in mind. As. stated above,

, AUTOMATIC TELEPHONE SYSTEM.

N0. 647,453. ReneWed .Tune 16, 1927.

the numbers are translated into the decimal system before being sent out to the automatic switches. This enables the standard ten step automatic switches to be used and permits the trunking local .to eachv olice to be laid out according to ythe trunking system which has become standard forsingiev ofiice systems and for the individual oiiices in a ymulti-oiiice system laid outV for use in connection with a decimal numbering system. l

It has been chosen to describe the invention in connection with a system having `an ultimate capacity of 160,000 lines. Since the twenty character system of notation is used, and since 204 is 160,000, each of the numbers for this system contains onlyfour characters, whereas six characters Aare required for each of the numbers in a system of the above size when the decimal system of notation is used. i Y

Since the system of notation used' employs 20 characters, and since there are 160,000 lines in the system, the system can be very conveniently divided into ytwenty offices of 8,000 lines each. In this case, the choice of ofices is made upon the first operation of the calling device. However,

when the standard` ten-step switchesare er'nployed for trunking, they cannot be utilized to their full capacity when an oiiice contains only 8,000 lines; thatl is, when only 8,000 lines are in an oiice, two levels of the thousands selectors in that office are dead. For that reason, and for the further reasonv that itis a practice long established to place approximately,10,000'lines in one office, it

has been decided to divide the system into 410, inclusive, should be placed together' in order to be understood.

Referring now particularly vtev Fig'. l, sin'd p teen rectangles, each representing an ofhce of the system, are shown therein. rectangles, as may be seen, are labeled office No. 1, office kNo. 2, etc., the numbers 1 to 4, 6 to 9, 11 to 14, and 16 to 19, inclusive, being used. Two torn'iulas, if they may be so termed, are written inside each rectangle and they represent the numbers that are assigned to each office. For example, the upper formula of office No. 1. represents 8,000 numbers and is 1-(1-20)-(120) (1-20), which means that all numbers beginning 'with 1 are assigned to this ofiice, the expression (1-20) meaning that the corresponding character maybe anything from '1 to 420. y

.It maybe here explained that in all prob- "abilityv .ten of the characters used for listing `fnuiribers ac'c'ording to the twenty character .system @if notation wiii be' the digits i, e,

etc. to 9, and O; and that the remaining ten characters will comprise ten letters of'v the alphabet.4 Notwithstanding this, however,

Vthe .aboveformulas as well-as the following `ones, arek for the sake of clarity, written Yj'iis't asthough the twenty characters are the numbers 1, 2,k etc. vto 20, with a dash separating each character from the others.

4 To ,resume the explanation ot' Fig. 1, the block of numbers beginning with 5 are divided into four Yequal parts of 2,000 numbers each, and one part is assigned to each of the firstfour offices, as is indicated by thelowerformulas of these offices. It is apparent from these Jformulas that, if the first .character of a number is 5 and the second character is anything from 1 to 5, inelusive, the number belongsto the first oflice, while if the first character is 5 and the second character is other than 1 to v5, in-

, elusive, the number belongs to one of the other ofices, either the second, third, or fourth. Acasual examination will reveal rthat the same general numbering scheine is v'carried out` for the remaining oflices.

Referring now particularlv to Fig. 2,

whichfis a more detailed layout of numbers assigned to o'liice No. 1, Fig. l, the numbers y are laid out in groups of 10'() each, ac-

cording .to the capacity of a standard connector switch. These groups are numbered from 11, in the lower lett hand corner. to 00, in the upper right hand corner, in accordance with the standard layout of a 10,000

,line office, using'ten-step thousands selectors andten-step hundreds selectors. i Since the system of notation used contains vrtwenty characters, and since twenty taken' .twice asa factor equals 400, the numbers vlmay be conveniently spl-it up into blocks of numbers each. That being the case, the 10,000 numbers of this office are divided into twenty-five blocks of 40() numbers each and the. first block of numbers in this ofice may be represented by the formula These first and second characters of all the num bers in this block are 1 and 1,7respectively,

while the third, as well as the fourth characters, run from 1 to 20. Since the capacity of a standard connector -switch `is Vonly 100 numbers, this ZL00 number blockl must beY split into four parts of 10() numbers each. The first part is represented by the formula is assigned to the four connector groups 15 18, inclusive, the third block to the first four connector vgroups inthe second thousand, which are the groups 21-24, inclusive,vthe fourth block to the nextwfour groups 2528, inclusive, whilethe fifth 400 number block is assigned to the ninth and tenth connector groups in the first and second levels which are the connector groups 19, 10, and `29, 2() respectively. This same'scheme is carried out Yuntil the entire 8,000 numbers beginning with 1 are assigned. `The remaining 2,000 numbers begin with 5 and are assigned to the last twenty connector groups 91-00, incluv sive, in the saine way as the first twenty connector groups 11-20, inclusive, the only difference between the numbers assigned to these two groups being in the first character,

which is V1 in one case and 5 in the other.A From the above it is thought that the nuinbeil layout-of, not only office No. 1, but also of Athe remaining offices canbe appreciated.

Referring now'particularly to Fig. 3, this is a drawing showing the relation `between the numbers aceordingto the twenty charac'- ter system and the actual numbers according to the positions to which they are assigned on the connector switches of the first 100 line group, Fig. 2. In this drawing, each rectangle represents one line oi' one positiony on a connector switch, and the number of each line according tothe decimal system, orY

rather the number corresponding `to its position in the connector bank is written in the 'upper portion of the rectangle, while the complete number of each line according toV the twenty character system iswiitten along the center ot the rectangle. It is seen that Y the 100 Vnumbers 1-1-1-'1 to`1'-1-5 20 are assigned in order to the 100 lines 11"to 00, inclusive. The same' scheine is carried out in each of the other connector groups.`

'Referring now particularlyto' Figs. 4410,

inclusive, Fig. 4 showsthe substation A, of

which the line comprising conductors 11 and 12 terminates at the exchange in the line switch C. The line switch C has access to the first selector D by way of the trunk with which the trunk circuit TC is associated. The secondary switch SS is associated with the trunk circuit TC and has access to a plurality of directors of which the one shown in Figs. 5-10, inclusive, is one.

The portion of the director shown in Fig. 5 vcomprises the controlling relays 101 and 102, and the sequence switches S and S; the portion of the director' shown in Fig. 6 comprises the relays 201-205, inclusive, and the sending switch SEN; the portion of the director shown in Fig. 7 comprises the first character register' R-l and the second character register R-2; the portion of the director shown in Fig. 8 comprises the third char acter register R-S and the fourth character register R-4; the portion of the director shown lin Fig. l9 comprises the four connecting relays shown; and the portion of the director shown in Fig. 10 comprises the intermediate distributing frame IDF by means of which the conductors associated with the sixteen offices can be cross connected with the condiictors of the sender in accordance with the inter-office trunking system.

The substation A is an automatic substation of the usual type and has, in addition to its talking and signalling arrangements, a calling device CD for controlling the setting of the register switches of the director. This calling device is designed to produce a maX- imum of twenty impulses in one series and, while the p-resent invention is not particularly concerned with any special mechanical embodiment, it will be assumed for the urpose of this application that the calling evice disclosed and described in the copending application of Blessing, S. N. 508,- 478, filed October 18, 1921, is the one used.

yThis'calling device is provided with the digits 1 to` 0, inclusive, and, in addition,`is provided with the letters A to II, inclusive, and the letters J and K, the letter'I being omitted in order to avoid its being confused with the digit 1.

vThe numerical switchesof this system, of which the switch D, Fig. 4, is shown, are

:mechanically of the well-known vertical and rotary type in which the bank contacts are arranged in ten horizontal rows or levels.

The line switch C, Fig. 4, is mechanically of the rotary type of switch in which the wipers have no normal position and move in a forward direction only. The secondary switch SS is of the same mechanical structure as well as the sequence switch S', and the sender SEN, Figs. 5 and 6, respectively. It may be pointed out also that each of these switches is of the particular type in which the wipers are advanced upon the deenergization rather vthan upon thezenergization of the operating magnet. A

The sequence .switch S, Fig. 5, is mechanically a simple switch having the wipers 108-111, inclusive, which are operated step by step in one lplane only bythe stepping magnet 103 and which arek restored to normal by the release magnet 104, which, in turn, is controlled by the 0E normal contacts 105. 'The register switch R-1-R-4, inclusive, Figs. 7 and 8, are mechanically similarto the sequence switch S and differ only as regards the number of wipers employed and as regards the number of steps taken. v Y

The IDF, Fig. 10, is provided for the pur-y pose of permitting the inter-'oilice trunking systemy to be laid out along the most economical lines, and, accordingly, .the conductors 331346, inclusive, and S51-366, inclusive, from-the banks of the wipers 312 and 313, 7, are brought over and connected upto the right hand side of the IDF in pairs, the first pair on the bottom being associated with oiice No. 1, the second pair with otlice No. 2, etc., as indicated'by the numerals placed immediately to the left of the terminals.

In order thatthe detailed operationofthe system can be readily understood, it will now be explained how a call is handled. It will be assumedxthat this `call is Voriginated by the subscriber at substation A and is intended for the subscriber whose directory number is 115K (K being the twentieth character on the calling device), and whose number `as sent" out byv the director, afterv Y being translated, is75-1100. The'digits 7 and 5, it maybe explained, are calledthe oiiice-digits on account of the fact that they effect the office selection, while the remain-V ing ones are called the subscriber-digits because they effect the selection of the desired subscriber after the call has been trunked to the correct oiiice.

Whenthe receiver is removed at substation A, line relay 14 energizes over line conductors 11 and`12. Upon energizing, line relay 14 places groundron private normal conducf tor 9 'at armature 20,. thereby making the calling line busy, and closing a. circuit for switching relay 18 and stepping magnet 15 in series. As a further result ofthe energiZat-ion Ofiline relay 14, it connects test wiper22 to the junction of switching relayv .13 and stepping magnet 15 at armature 19.

lIn case the trunk upon which the wipers of theswitch are standing is idle, switching relav 13 energizes immediately. the trunk to be busy, however. switching relay 13 is short circuited by the ground potentialencountered by ytest wiper 22 onrthe busy test contact and does not energize, and

Ythe wipers arerotated step by step by the l.buzzer-like action of stepping magnet 15,

which is operated through test wiper 22.

`"When an idletrunk is reached, which trunk it will be assumed'is the one terminating in banlr contacts 24-26, inclusive, switching relay 13, vbeing no longer short circuited, energizes in series with stepping magnet 15.

Assuming Y Stepping magnet 15, however, does not energize at this time on account of the high resistance of switching relay 13. Switching relay 13,V upon energizing, opens a point in the Ltest circuit and prepares the holding circuit at armature 17, and at armatures 16 and 18 disconnects line conductors 11 and 12 from the winding of line relay 14 and ground, and extends them by way of wipers 21 and 23, bank contacts 24 and 26, conductors 27 and 29, and armatures 79 and 81 and their resting contacts, to the upper and lower windings of line relay 75 of the trunk circuit TC. Line relay 75 now energizes over the calling subscribers loop and closes at armature 78 a circuit for line relay85 of the secondary switch SS. Line relay 85 energizes at this time Vand places ground on release trunk conductor 28 at armature 88, thereby establishing a holding circuit for switching relay 13 of the line switch C before the slow acting line relay 14 has had ltime to deenergize.

As a further result ot the energization or line relay 85 of the secondary switch SS, it lcloses at armature 89 a circuit tor switching relay 86 and stepping magnet 87 in series,

' and at armature 90 connects test wiper 97 to the junction of switching relay 86 and stepping magnet 87. The further operation of the secondary switch SS depends upon whether the director upon which it is standing is busy or idle. In case it is busy, release trunk conductor is grounded and the secondary switch operates in the same manner as the line switch C and selects an idle director. It will be assumed in the present case, however, that the director upon which the wipers of the secondary switch are standing is idle, and in that case, no hunting operation takes place and switching relay 86 energizes immediately in series with the low wound stepping magnet 87 As a result of the energization ot switching relay 86, ground is placed on release trunk conductor 70 at armature |93. This results in the release relay 201, Fig. 6, becoming energized over conductor 70. The energization of this relay, however, is merely a preparatory operation and does not produce any immediate eitect. Asa further result of the energization of switching relay 86 of the secondary switch SS, the impulsing circuit for the director is prepared at armature 94, and a bridge is closed across the line conductors 30 and. 32 extending to the selector D at armaturesV 91 and 92. This bridge includes the secondary switch wipers 95 and 96, conductors 68 and 69, resting Vcontact of armature 231 and said armature,

Figi, and armatures 210 and 212, and their resting contacts. Line relay 41 ot' the selector D now energizes over this loop and closes a circuit for release relay 42 at ary mature 52. Release relay 42, upon energizing, opens a point in the circuit of lrelease relay 46 and prepares a circuit for vertical magnet 47 at armature 54, and at armature 53 places a ground upon release trunk conductor 31, thereby preparing certain local circuits :tor relays 44 and 45 and for rotary magnet 48 which will be completed subsequently. The selector D is now ready for operation.

Then the subscriber at substation A opcrates his calling device CD in accordance with the iirst character (the digit 1) in the desired number, one interruption is produced in the circuit ot line relay 75. -Relay thereupon deenergizes once momentarily, and at armature 77 places ground -on the impulse lead 71 of the director. This results in an impulse of current being trans- 'mitted to the operating' magnet 301 ot the register R-l, Fig.V 7, by way of the slow acting series relay 101, Fig. 5, `the impulse .distributing wiper 1116i the sequence switch S, and conductor 112. Upon energizing in response to this impulse of current, operating magnet- 301 advances the wipers 311-313,A inclusive, into engagement with the rst set ot' associated bank contacts. Series relay 101 is energized at this time,rand closes a circuit for the slow acting relay 102 at. armature 106. Relay 102, accordingly, energizes and prepares a circuit for theoperating magnet 103 ot' the sequence switchS at armature 107. Then when relay v101 deenergizes upon the termination of the limpulse of current sent through it, it opens the circuit o't the slow acting relay 102 andcompletes the circuit of the stepping magnet 103. Relay 102 is slow acting,'and for that reason maintains armature 107 attracted sufficiently long to permit the magnet 103 to be operated after which it deenergizes and opens the circuit of magnet 103. By the operation of magnet 103 the wipers 108411, inclusive, of the sequence switch S, are advanced into engagement with the second set ot bank contacts. Viper 111, it will be noted, shifts the impulse lead trom conductor 112 to conductor 113.

Vhen the calling subscriber manipulates his calling device CD in accordance with the second character (the digit 1) in the desired number, line relay 75 of the trunk circuit TC responds by sending an impulse otcurrent over` the impulse lead 71 and'through the series relay 101, Fig. 5. Since wiper111 is at this time in engagement with conductor 113, the stepping magnet 304 ot the second .digit register R-2 is at this time operated, and accordingly the wipers 321-326, inclusive, of the register R-2, are moved into engagement with the. first set of bank contacts. y Y

Upon the termination of this impulse the wipers ot the sequence switch 'Sjare advanced another step in the manner described ing the conductor 141.,

above, thereby shifting the .impulse'lleady-at wiper 111 into, engagement'withiconductor 114. extending to the .operating magnet' 401 otthe-.registerR95.I .Y V l g Since the tirst two characters in the desired number have been registered, and since Vit never requires more than two characters to determine the desired ohce, thesending equipment may now be permitted to operate to bring about the selection of the desired otlice. `Tlie operation of the sending equipment is 'initiatedvat this time upon the wiper 108 coming into engagementfwith the third associated bank contact and thereby ground- The description of the operation of the, sending equipment,l descrip however, will be deferred until the tion of the setting of the register switches has been completed.

v When the vcalling device ACSD at the substation .A isoperated in accordance with the third character (the digit 5)l inthe desired number, line relay 7 5 of the trunk circuit TCr` is.y deenergized d five times imomen'tarily,y Vand upon eachv deenergization sendsl an impulse of current overthe operating circuit through 'the' series', relay 101 and wiper-111 (now-in yengagement with the third bankcontact), to

`R-4. Stepping magnet 404 Yeijrng to Fig. 1.

the steppingy magnet401 otthethird .regis-1 ter R-l-S, by way of lconductor 114.A By the o peration ot stepping magnet 401., the wipers 411-417, inclusive, vof the registenR-Sare advanced step by step into engagement with the tth set of bank contacts. f Series'relay 101 is energized as usualy upon the -irst impulse being transmitted through it, and be# ving slow acting maintains its armature 106 attracted th youghout the ,series of impulses,`

denergizes upon the stepand when relayA 101 Ytermination ofI thel series 'of impulses,

ping .magnet 103 is again operatedandtlie f wipers .108-111, inclusive," of the-sequence switch Sv are advanced intoengagement with thel fourth set ofl bank contacts.

`Whenvthe calling subscriber manipulates his calling device CD in accordance with the iourthA character '(the letter in .the desired number, line relayrespondsby. 'momentarily Ydeenergizing twenty times. This results in twenty impulses of currentbeing sent over the operating circuit andthrough Vseries relay 1014 to fbyway-of the fourth contact inthe bankof ated pawl into the wiper 111,and thence the inter-oticetrunking system is suchv that, in orde-rffor acall to be-trunked from the oihce in'whiy h` the line of substation A terminates tooice No. 1, two digits must be sent out by the sending equipment. It willl be assumed that these digits are 7 and 5, respectively.v Accordingly, the tirstand second tively, Fig. 10, otoilice No.1, are connected at the intermediate distributing rameIDF by means ofl the jumpers ,401 and 402 to the seventh l and, fifth impulse stop conductors, respectively.4 With these fact/sv in mind, the subsequent operations may now be appreciated. f L v v Y `As pointed `out lhereinbefore, when wiper 'digit stop conductors 351l andV l331, respec- 108 .of thesequence switchy S, Fig. 5arrives uponv the. third associated .bank Contact at f `the1end ofthe registration of the second oharactergin the called numberfit places ground on conductor 141. This results in 'ground being placed onvstart vconductor 139 through the first contact. in-r the bank of wiper 134.015 the sequence switch S and said wiper.v Zhen this occurs,fa circuit is closed over start5conductor139 for sendingrelay 202 including farmature216A andV its resting contact, armaturev 2719 land its resting-contact :and th constantly 'operating'- interrupter .2271.- .Relay .202.. accordingly, starts Y to energize anddeenergizeunder the control of interrupzter 221, and upon itsfli'rst eeotive energization acircuit is close-d atarmaylture 2111/1101' stepping magnet 222' of ,the sending switch SEN, Stepping magnet 222 thereupo'nfenergizes and ymoves the associengagement withY the. next notch inthe associated wiperdriving ratchet wheel. Tliifcloes not move the''wipers on ,tlieswitcli v Upeehenext relay l 2 02, th'eycircuit of steppingV magnet 222 is opened armature '211, whereupon magnet `222 `,dee'nergizes Rand permits-the wipers 224 and c l225l to clockwise direction into engagement Li'vithithe first. setof associated bank contacts. Wiper V.225, yupon engaging.,'itsz second. bank contact,

completes a circuit, forpickup relay flickfup relayl r203A now energizesand pre# pares a locking ycircuit for stop relay" 204 i at armature I21,4, and. at armature 213 closesa `circuitgtrom I ground through the resting con- Ltact ot armature 215rand said armature and overfconductor 138 for stepping magnet 131 'or' the sequence switch Upon energizing, stepping magnety 131: movesV inthe wiperv driving ratchetwheehbut does `notmove the wipers of ythe switch. .Asia

.turtherresult of the energization of up relay 208, Fig.v 6, it. removes at. armature 212 the shunt from around-armature 210 of sending' relay. 202fandfi'ts restingfcontact, thereby leavingthe bridge across the talking deenergiz'ation of sending ilo y y .the associated f ypanvlwinto engagement with the next notchy y 215 opens and 225I are advanced into engagement withy the second set of associated bank contacts.'

This brings wiperv 224'into engagement with* the contact. in which the first vstop yconductor is terminated. This stop conductor is not connected upy to ground at thistime, however, and accordingly this is without effect.Y

The operationl 'of the sending relay 202 and the sender SEN continues as described until :seven interruptions vhave been lproduced at armature 210* in the outgoing control circuit. VThe seventh "interruption is produced While 7the 'wiper 224 is on the seventh associated bank contact, and upon its termination by relay 202, the wiper 224 is advanced into. engagement with the eighth associated bank 'contact'thereby closing a circuit for stop ref lay' 204 las -follows: From ground by Way of the stop conductor control wiperf135 of sequence switchV S", Fig. 5,-the first associated bank contact, the first otticedigit stop conduct-or 151, wiper 313 of therst register vswitch Ree-1, the yfirst associated band contact, condu'ctorr351, jumper 401 of the vintermediate distributing frame IDF, Fig. 10, the. seventh impulse stop conductor, the associated Contactin the bank of wipery 224 of vthe sending' switch SEN, Fig. 6, wiper 224, and stop relay 204 to battery. Stop relay 204, upon energizing over this circuit, comjpletes a locking circuit. for itseli'v atarma ture. 217 disconnects sending relay 202 at armature 216 while the said'rela-y 202 ,is still inY a"dee1'iergized condition; and at armature f ,Y the circuit otstepping magnet 131 of thesequence the wipers 13B-135, inclusive, are advanced intoengagement with Vthe second set of bank contacts.k Viper 135, it will be noted, removes ground .from lthe first office-digit stop conductor 151 and places it upon the Second votliee-digitl stop conductor 152.

In the sending equipment, Fig. 6, as a ystill further result of the energization of stop relay'20-4, it connects the stepping magnet 222 `to wiper 225 at larmature 218, whereupon 'the' wipers 224 and 225 kare rapidly Vspun jaround 'to their normal position owing to the buzzer-like action of stepping magnet 222 which interrupts its own circuit at contacts 223. Then wiper 225- paSses ofi` the last vries' with'vertical magnet 47, and acting maintains its gagement with the lirstv set` of con-tactsin switch S., whereupon at rn-terrupter contacts 50.

grounded b'andicontact the automatic opera# tion of magnet222 ceases and the circuit of the selector D will be described. It willy be l remembered that the circuit of line relay 41 ottlie selector D4v was opened sevenA times momentarily atarmature 210 oit sending re lay 202 during the travel ot' the wipers lot the sending switch SENA lunder the controlot the ksaid sending relay 202. Line relay 41 ot' the'selector D, accordingly, deener- `gizes in response-to each ofV the seven linterruptions produced i-n itscircuit, and closes at armature 52 a circuit for vertical magnet 47 asfollows: From ground' by way of the resting `contact ot armatureO and ,Saidf armature, a-rmature-52- and its-resting contact, arn'ia'ture 54 and its working contact, slowV actii'ig'series relay- 43,an'd vertical magnet 47 to battery.' Bythe operationyof'vertical magnet 47 the wipers (i2-64, inclusive, of the selector D are raisedfstep by step-'and come to rest opposite Vtheseventh 4Vlevel of vbank contacts. Relayelf?)` isenergized in se' armature 55 attracted throughout the vertical movement. 'Y Upon the closure ot otf normal contacts 51, which occurs at the end of theV lirst-:vertical step, a circuit is closed 'for stepping'relay 441 as follows: From'ground by way ofthe working contact ot armature 53 and sai-d armature, armature '55 and its working Contact, fett normal `contacts 51, interrupter contacts being slow 50, and steppingrel-ay 44 to batteryf'Stepping relay 44,.upon energizing, closes Va lock- Y ing circuit forfitselt at armature 56, and at armature 57 Y magnet 48d.:

At the end of the vertical movement,sl`ow acting series relayf43 d'eenergizes and com-y pletes 'thecircu'it otrotary magnet 48. lR'otarymagnet 48 thereupon eneigizes and adprepares a circuit forfrotaryl vances the wipeis'YG2464, inclusive, into en'- theselected level, and (nearthe end of its stroke opens the circuit of stepping relay'44 Stepping relay 44,'upon deenergzin-g, opensv the circuit Vof rotary magnet 48 at armature?, whereuponfrotary magnet 48 deenergizes and closes its interru'pter contacts-again. 1 The further opera-tion of tlie'selector D now depends upon whether'the trunk terminating in the lirst setV of bank contacts in the selected level'is busy or idle. It it is. idle, switching relay 45 energizes immed'i ately' in series with stepping relay v44'. Assuming it to 'be busy,-however, switchi-n-gre lay 45 is short circuited bythe ground potential encountered on the'rb-usy test contact by'test wiper 63, and stepping relay 44 en` ergizes through the test wiper 63 and again closes the circuit of rotary magnet 48 at armature 57, whereupon the wipers of the Switch arel advanced into engagementvwith the second set of bank contacts.

rotaryl magnet continues as described until an idle trunk is reached, which trunk, it will be'assumed, is the one terminating in' bank contacts 65-67, inclusive.Y lVhen this occurs, switching relay`45 is no longer short circuited and energizes in series with stepping relay 44. .Stepping relay 44, however, does not energize at this time owing tothe high resistance of switching relay 45. Upon en'- ergizing, switching relay 45 disconnects ground from armature52 of line relay 41 atV armature 60', thereby opening the circuit of slow act-ing release relay 42; disconnects test wiper 63 from the junction of switching relay 45 and stepping relay 44 and connects it to the grounded release trunk conductor 28 at armature 59, Vthereby making the seized trunk busy immediately; Aand at armatures 58 and 61 disconnects the line conductors from the windings of line relay 41 and extends them byway of the working contacts of armatures y58l and 61, wipers 62 and 64, and bank contacts 65 Vand 67 tothe line relay of the selector switch to which the seized trunk extends.

The line and release relays of the seizedy selector switch now energizes in the usual manner and the latter places a ground potential on the associated release trunk conductor, thereby closing va holding circuit for t-he vswitching relay 45 through test contact 66, test wiper 63, and armature 59k and its working conta-ct. This ground potential ex tends back over release trunk conductor '28 to the switching relay 13 of the line switch C and maintains that relay energized. 1t will be understood, ofy course, that this ground potential is applied to the release. trunk conductor bythe seized selector switch before the slow acting release relay 42 of the selector D has had time to deenergize.

Returning now to the sendingequipment of the director, the slow acting pick-up re-v lay 203 deenergizesafter any interval and.

opens the circuit of the slow acting stop relay 204 at armature 214. Slow acting stop relay 204 also deenergizes after an interval, and again connects up the sending relay 202 atarmature 216. The `interval required for the slow acting relays 203 and v204 to fall back vone afterA the other is utilized as above described by the selector D in changing over and selecting a trunk afterV thev vertical movement has been effected.

Sending relays 202 now starts to vibrate again under the control of the interrupter 221, with the result that the sending switch SEN is operated as before to count olf the This alter'` nate operation of the stepping relay and theV number of interruptions that are produced inthe outgoing control circuit at armature 210. This second series of interruptions, representing the second ofiice-digit, comprises five `interruptions and is terminated when stop relay 204 energizes over the following circuit :V From ground by way of the stop conductor control wiper' 135 of the sequenceswitch S, the second associated bank contact, the second oiiice-digit Ystop conductor 152, wiper 312y of the register switch R--1, Fig. the firstv associated bank contact, conductor 331, jumper 402 of the intermediate distributing frame IDF, the fifth impulse stop conductor, and thence to battery through wiper 224 of the sending switch SEN and stop relay 204. `Upon the energization vof stop relay v204 the wipers'of' the sequence switch S are advanced one step in theA manner described above, and the wipers of the sending switch SEN are again spun around'to their normal position, after which the slow acting relays 203 and 204v fall back one after the other to start the sendinfr out of the first digit in the desired subscribersl number. l

In response to the five interruptions produced in the outgoing control circuit in accordance withithe second office-digit 5, the selector switch which was seized as above described by the selector' D, Fig. 4, raises its wipers to the fifth level and selects an idle trunk extending to a thousands selector in office No. 1. i i

'The sending relay 202 now starts to oper` ate under the control of interrupter 221, with the result that the sending switch SEN is stepped around to count off the interruptions produced in the outgoing control cire cuit. The first digit in the subscribers number as translated is 1, and accordingly stop relay 204 is energized at the termination of the first impulse `produced in the outgoing control circuit. .Relay 204 is energized at this time over the following circuit: From ground by way of stop conductor con'- trol wiperV 135 of theV sequence switch S, the first subscribed-digit stop conductor 161,

wiper 311 of the first register switchv R--1,

the first` associated bank contact, conductor 425, wiper411y of the third register switch it-3, the fifth associated bank contact, conductor 427, wiper 321 ofthe second register switch R-2, the first associated bank con# tact, the first impulse stop conductor, and thence to battery vby way of wiper 224 of thesending switch SEN and stop relay 204.

This one interruptionproduced'in the outgoing control circuitfca'uses the thousands selector to which the vconnection has been extended to raise its wipers opposite the first level ofy bank contacts and select an idle hundreds selectori'n thef rst thousand .of

After the usualintervalbrought about by the slowness of relays 203 and 204, Fig. 6, the sending equipment starts operating again for the second or hundreds digit 1 in the subscribers number. It will be understood, of course, that the sequence switch S. was advanced one step as usual in response to the sending out of the first digit 1, and that the wipers thereof are now in engagement with the fourth set of bank contacts.V

That being the case, stop relay 204 is energized following the termination of the first interruption in the outgoing control circuit over a circuit which is as follows: From ground by way of the stop conductor control wiper 135, the second subscriber-digit stop conductor 162, wiper 324 of the second register switch R-2, the first associated bank contact, conductor 429, wiper 415 of the third register R-3, the fifth associated bank contact, and thence by way of the first impulse stop conductor to battery through wiper 324 of the sending switch SEN and stop relay 204. y

In the exchange No. 1, the hundreds selector to which the connection has been eX tended raises its wipers to the first level in response to the sending out of the above digit, and selects an idle connector switch 1n the first hund-red of the first thousand lines.

The sequence switch S is automatically advanced another step and the'k sending equipment again starts to operate. The third digit in the called subscribers number is 0, and accordingly at the end ofthe tenth interruption produced in the outgoing control circuit stop relay 204 is again energized in response to wiper 224 of the'sendn ing switch SEN arriving upon the tenth impulse stop conductor. The circuit of stop relay 204 at this time is as follows: From ground byway of the stop conductor control wiper 135 of the sequence switch S', the fifth associated bank contact, the third subscriber-digit stop conductor 163, wiper 421 of the fourth register switch R-4, the twentieth associated bank contact, conductor 432, wipers 413 lof the third register R -3, the fifth associated bank contact, and thence to battery by way of the tenth impulse stop conductor, wiper 224 of the sending switch SEN, and stop relay 204. The sequence switch S is automatically advanced one step at this time and arrives on the sixth set of bank contacts.

In the office No. 1, the connector switch to which the connection has Vbeen extended raises its *wipersV opposite the tenth level of bank contacts in response to Vthe sending out of the third digit 0 in the desired subscribers number. y

Thev sending switch SEN is again started and this time counts ofl' the interruptions produced in the outgoing control circuit in accordance with the fourth digit 0 in the desired subscribers number, and upon wiper the 'following circuit: Fromground by way of the stop conductor control wiper 135, the fourth subscriber-digit Astop conductor 164 wiper 422, the twentieth associated bank contact, and thence to battery by way of the tenth impulse stop conductor, wiper 224 of the sending switch SEN, and stop relay 204. 'Ihe sequence switch S is now advanced another step, and its wipers come into engage'- ment with the seventh set of associatedbank contacts with results which will be pointed out hereinafter. y f

In the oliice No. 1, the connector switch to which the connection has been extended LArotates its wipers in response to the fourth and last digit'O in the desiredv subscribers vnumber into engagement with the tenth `set of bank contacts in the tenth level, and starts to ring the desired subscribers bell. Y

In the director, wiper 135 of the sequence switch S upon coming into engagement with the seventh associated' bank Vcontact `as pointed out above, places ground on the incoming impulse conductor 71, thereby closing a circuit over the said impulse conductor for switching relay 76 of the trunk circuit TC. This'circuit includes armature 77 and its working conta-ct'of line relay 7 5, and the normally closed contacts controlled by arma-y ture .80. YSwitching relay 76, upon energizing, locks itself to the grounded release trunk conductor 28 and opens its vinitial circuit at armature 80 ;y connects release trunk conductors 31 and 28 together. at armature 83; and at armature 79 and 81 disconnects line conductors 27 and 29 from the windingsy of line relay 75 and extends them to .the .cor-

responding conductors 30 and32 ofthe selector D, at the same time disconnecting the said conductors 30 and 32-of the selector D from the control circuit coming from the director. The connection is ,now under the direct control of the calling subscriber. Line relay 75, upon deenergizing in response to being disconnected, opens the circuit of relay 85 at armature 78, whereupon relay' 85 deenergizes after .the interval for which it is adjusted and opens the circuit of switching relay 86; Switching relay 86=now deenergizes and disconnects its wipers, thereby freeing the director and removing ground from conductor 70. i

YIn the director, when ground is removed from the release trunk conductor 70, res lease relayY 201 deenergizes and places ground on the com-mon .release conductor Yat armature 209, thereby closing a Vcircuit which vincludes release magnet 104 ofthe sequence switch S, release magnet 302 of the firstV register switch R1, release magnet 305Vof the second register switch R-f2, re'- lease magnet 402 of the third 1register switch lau register switch R-4. These releasey magnets accordingly energize vand restoreiltheir respective switches to normal position, and their circuits are opened by their respective associated off normal contacts when the ,y

translated in accordance with the lnumber associated wipers reachr their normalpositions. It may be pointed out that the circuit of release magnet 104 of the sequence switch S is opened'at off normal contacts 1 05, and that the circuits of release magnets 302, 305, 402 and 405 of the registers R-.1-R-4, inclusive, are opened at off normal contacts i 303, 306, 403 and 406, respectively.

YAs a further result of the deenergization of release relay 201, Fig. 6, it closes at armature r206 a restoring circuit for stepping magnet 131 of the sequence switch S. This circuit includesthe conductor 136, wiper 133, and interrupter contacts 132 of the stepping magnet 131. Accordingly, the stepping magnet 131 operates in a buzzer-like manner and advancesA the wipers 133-*135 to their normal position. y y

As a still further result of the deenerL gization of releaserrelay 201, it places a shunt around armature 213 and its working contact of stop relay 204 at armature 208, thereby connecting Wiper 225 with the stepping magnetl222' through the interrupter 223. This is the usual Arestoring circuitfor the stepping magnet 222, but it is not effective at this time since thevwipers are already',

This circuit, it may in a normal position. y g be pointed out, is brought into play, however, when the calling subscriber hangs up and brings about the release of the director while the sending switch is olf normal.

The directorzis now completely restored to normal and is ready to be used in a subsequent call.

Returning now to the established connection, when the called subscriber responds, the ringing current is cut oil' in the usual manner and conversation may. take place, and when the conversation is terminated and the calling subscriber replaces his receiver, the connector switch in use is released in the usual manner and removes ground from the associated release trunk conductor, thereby permitting the various selectors included in the connection, of which the selector'l), Fig. 4, is one, to release. The release of the selec-v tor D, it may be pointed out, is brought about upon the deenergization of switching relay 45, which closes at armature 60 a circuit for release magnet 46 through armatures 52 and 54, and off normal contacts 49.

The circuit of releasemagnet 46 is again opened at oli normal contacts 49 by the switch shaft When the latter reaches normal-` position. The circuits at the line switch C and the trunk circuit TC assume normal condition u on the deenergization of the relays 13 and 6. The entire connection is now vreleased and the apparatus used therein is ready to be used in a subsequent call.

Referring now particularly to Figs. 1-3, inclusive, and to Figs. 7-10, inclusive, it will now be explained more in detail just how the, numbers received by the director are ass'ignment indicated in Figs. 1-3, inclusive.

It is obvious that'tlie wipers 313 and 312 of the first register R-1, Fig. 7, connect up the first and second office-digit stop" conductors 151 and 152, respectively,A to the desired set of terminals on the right hand side of the intermediate distributing frame, IDF, Fig. 10, when the first character in the number is not 5 or divisible by 5, as in that case the first character alone determines the office to which the call is going. In case the y first character is 5, or divisible by 5, that character does not determine definitely the oiiice to which the call is going. This can be readily seen by. referring to the systemV lay-A out shown on Fig. 1,'which plainly shows, by means of' the lower formulas written inside the various rectangles, that when the character 5 is the first character, thel call may be intended for either of the first foury Similarly, if'the first character is `divisible by 5, such as 10, 15, or 20, thecall may be for any one of four different oflices. Y

offices.

nates in oflice N o. 2, etc. Accordingly, when the first character is 5, or divisible by 5,

the wipers 313 and 312 yare stopped on contactswhich are not connected with the IDF. Then, when rground is placed on start conductor 139, Fig. 5, at the end of the operation of the second register R-2, as described hereinbefore, a circuit is closed over thestop conductor control wiper 135, the first digit stop conductor 151, wiper 313 of the first register R-l, the bank contact with whichA it is in engagement, (say the fifth),.conduc tor 371, normally closed contacts controlled by armature 305, and relay 301 to battery. t

Relay v301, upon energizing, locks itself to conductor 70 andopens its initial circuit at armature 305,*and at its four left hand arma-V tures connects the four conductors381-384, inclusive, coming from the bank of wiper 325 ofthe second register R-2, to the conductors 351-354, inclusive, extending'to the -lower terminals of the first four sets on the right handside of the IDF. As a further result of the energization of relay 301, it con`r nect's at its four right hand armatures, the four conductors 391-394,V inclusive, coming from; the vbankof 'wiper 326LA of the secondv register*R,'--2,' to the four conductors 331- 334,'inclusive, which areconnected to the upper terminals of the first lfour sets on 'the right hand side of the IDF.v Vith these Y 45, and'i'fit is determined-"that lthe call is conductors so connectedfsince the first and second oifice-digitv stop conductors 351 and 352 are connected to the wipers 325 and 326, respectively, of the second register `R--2, the

first and second office-digit stop conductors` arey lextended'through to the vcorresponding terminals" of' one of the firstfour ofiic'es 'on the right hand iside' of the* IDF, depending,V

of'course,upon the secondcharacter inthe number received. n

Incase the registerR--1 is set upon the tenth set yof contactsrelay 302, instead vof 301,'is operatedy over conductor 37 2 and connects the conductors comingfrom theI banksy of'wipersy 325v and 326to the conductors 335" to'33'8: and conductors 355 to 35,8, inclusive,"

associatedl with the offices v6-9, inclusive;

Similarly, `if the `wipers of the register R441 are set on the fifteenth set of bank contacts, 'relayr303 is operated over conductor 37 Bandconnects the conductors 381-384,in-

elusive; and 391-394, inclusive, tothe conductors '4369-362, inclusive, and-3394342, inclusive,` respectively, which lare'` associated with the oices y11414", inclusive. Y

It'f may alsor` be seen that the lwipers of the registeriR-fl are set upon the twentieth set ofbank contacts, the'relay 3.04 isoperated over conductor 374 and `connects the' con- ""dl`ctorscoming from the banksof thewipers" clusive, and 3635-366', inclusivenwhich extend tolthe contacts y'on the right `hand side: of

the`-intermediate distributing fffle IDF inclusive.'

that arejiassociate'd with the'oifices'1619f From'the foregoingitmay be seen howv the 'registersR-l 'and R`2 andthe relaysj f 30114304, inclusive, yco-operate to connect the 'first' and second lcnice-digit stop conductors tothe correct set of 'terminals' on` the right handlf'side' 0f the IDF, sothat the'call may be trunked to the desired office; According-1 ly;,fitwill now be explained how the lselection ofj the correct thousand is elfe'c'ted.

set'of bankcontacts, in which case the'wiper" 311:1;of theregister R-l extends the first subscriberdigit'stop conductor 161to wiperr 3235:l rlliegwiper 323, as vwell' asthe wiper 414; has to choose between, onlyy two digits 9 and 0.` This-canbe understood best by re-v ferring'to" 2, inwhich vit will lbe noted necaeeo thatif the first characterin the number is intended-for office No. 1, that the'thousands?i digit `must be either 9 or 0, because all the numbers in office No. 1 beginning with the f character `'ar'e in theninth and tenth `thou' sands. f Thesame :ruleV applies tothe remain-"V 'ingoffices It willbe noted that if the sec-vond 4character inthe number 'is 1 or 2 thel number belongsto the ninth thousan'd'fw'hile if thejseco-nd character is' 3 or4, the number 'belongs to the tenth thousand. Accordingly, 'n ithe first andsecondfcontactsin the bank 'or' wiper 323.,.Fig. '7,v are connected to theninth impulse' stop conductor, `and 'thef-third'and* lfourthcontactsare connected 'to the tenthy impulse stopfcond'uctor.l It willbe notedfl further that if the second character inthe n number is 5,' the number may bein Ieither whether the third characterr l'is from -1-10,

. the ninth or tenth thousand, depending upon inclusive, or from`11-20, inclusivelAccordL'uingly, thel fifth contact in the bank Pof wiper 1" 323 is connected through" conductorf428 tof' `wiper4l4f of the third"register switch ,RifjrY and lthefirst ten 'contacts in the"bank of wiper l41"'4 are' connectedto'thefninth im?V pulse stop conductor,` whilenthe remaining? i ten are connected to 'thetenth impulse'fsto'pf conductor;v The remaining contactsinith'e i banlrof wiper' 323 are'similarlv connectedv i cui up; l Y

Iti will be noted `that ifwipern311f'ofthe:k

digit stop conductorV- 161 third register .switch R3.v Thev contacts in first y register switch Rei-1 stops on any fof fthe. bank V"contacts other thanthe fifth, tenth,

fifteenth, ortweiitieth,y the first;subscribe'r-'l v l n n is connected through conductor'425` to' wiper 411 ofthe v the.; bank of ivipe`1f411`are, in'turn, connected 'A through conductors `426 and 427 to therwip`V -ers 321'and 322of the second-register switch llt-#2. I The bank contacts L of the wipers- 321vv and 322 Aareboth connected up'n the same' way except las 'regards the fifth; tenth, Yteent'hiand twentieth sets. Accordingly, 'in

case the" settingjof the 'register Rel cates vthat the knumber is assigned tok one ofthe first 8000 lines'in an oiii'ce', thev oiiicu'eVIV No. for exainpldfjand incase they secondi j register R42 isset on a set of contactsother n than'the fifth, tenth, fifteenth :or twentieth,"

the setting of wiper 411'of; register switchf" R-3 does not produce'anywchange; in theY 1 thousands digit'owinggto the fact pointed;` vout, above, that'the banks of wipers 321l andek ,322 arerwired bothexactly the sameexcept as regards the Contacts 5.10',115 31162011 Referring now particularly toEigr2Vit* will'beA noted that if the firstgcharacterinthe; v

5 lio" number is'1,"'(r`esultingin the"call""being 

